floating ip address conflict error during migration

[archerwu9425]

/kind bug

What steps did you take and what happened:
I have created floatingippool, and add ipadressclaim for cluster A to assign floating ips for specified machineDeployment.

When I migrate cluster A from management cluster B to management cluster C, I met ip address conflict error:

Error: [action failed after 10 attempts: error updating "ipam.cluster.x-k8s.io/v1beta1, Kind=IPAddress" <cluster-A>/<cluster-A>-worker-cloud-alln-1-c-srl9m-fz8lp-floating-ip-address: admission webhook "validation.ipaddress.ipam.cluster.x-k8s.io" denied the request: spec: Forbidden: IPAddress spec is immutable. Diff: v1beta1.IPAddressSpec{
    ClaimRef: {Name: "<cluster-A>-worker-cloud-alln-1-c-srl9m-fz8lp-floating-ip-address"},
    PoolRef:  {APIGroup: &"infrastructure.cluster.x-k8s.io", Kind: "OpenStackFloatingIPPool", Name: "us-txccnci2"},
-   Address:  "10.xxx.xxx.89",
+   Address:  "10.xxx.xxx.230",
    Prefix:   32,
    Gateway:  "",
  }, ...] 

The new ipaddress 10.xxx.xxx.230 is created in the new management cluster C before the old ipaddress 10.xxx.xxx.89 which is attached to the original node migrated to it.

What did you expect to happen:

1. When cluster is paused in new management cluster C during migration, no new ipdress should be created (reconcile should be paused)
2. After IPAdress migrated, reconcile should ensure the node has exactly the same ipadress.
   Anything else you would like to add:
   [Miscellaneous information that will assist in solving the issue.]

Environment:

• Cluster API Provider OpenStack version (Or git rev-parse HEAD if manually built):
• Cluster-API version: v1.10.9
• OpenStack version: v0.12.6
• Minikube/KIND version:
• Kubernetes version (use kubectl version): v1.33.7
• OS (e.g. from /etc/os-release): Ubuntu 24.04.3 LTS"